1. Field of the Invention
The present invention relates to an original cover closer for use on a copying machine or printing machine (will be referred to simply as "copying machine" hereinafter), and more particularly, to a closer for an original cover on which a heavy automatic document feeder is provided.
2. Description of the Prior Art
To copy a thick original such as a book, a well-known original cover closer comprises a mounting member to be installed on a copying machine body, a supporting member pivotably supported on the mounting member, a lifting member pivotably supported on a free end of the supporting member and to which the original cover is secured at the rear portion thereof, a resilient member provided between the mounting member and the free end of the supporting member, and a controlling member which controls the motion (turn) of the lifting member away from the supporting member.
Conventionally, in case a heavy automatic document feeder is additionally provided on the original cover and its center of gravity lies at the middle between the right and left of the original cover, a single large-torque closer is used with the original cover to support the latter at the middle portion thereof where the center of gravity, namely, the most of the weight, of the automatic document feeder is applied.
FIG. 1 shows the basic concept of the present invention will be outlined below. The original cover with which the closer of the present invention is used is generally indicated with a reference 1. It has a center of gravity 2. An automatic document feeder 3 is provided on the original cover 1. In case the center of gravity 2 should unavoidably be placed at either the right or left of the original cover 1 because of a geometrical relation between the original cover 1 and automatic document feeder 3, there must be provided an original cover closer A of one type destined to keep the original cover 1 at an intermediate opened angle and prevent it from falling abruptly and in addition an original cover closer B of another type destined to well balance the right and left of the original cover 1 and thus facilitate a smooth operation of the original cover 1 when closed or opened.